Technical Description of OBD-II Trouble Code
Generic: Low Circuit for Turbocharger/Supercharger Boost Sensor “B”
What is the meaning of this?
This is a generic diagnostic trouble code (DTC) for the powertrain that applies to all vehicles with turbochargers or superchargers. This includes brands such as Audi, Nissan, Mitsubishi, Mazda, VW, and others.
The powertrain control module (PCM) uses a sensor called the manifold absolute pressure sensor (MAP) to monitor boost pressure. Understanding how the MAP sensor works is the first step in explaining the cause of P0241.
The PCM sends a 5 volt reference signal to the MAP sensor, and the MAP sensor sends a variable voltage signal back to the PCM. When the boost pressure is high, the voltage signal is high. When the boost pressure is low, the voltage is low. The PCM uses the boost control solenoid to regulate the amount of boost pressure produced by the turbocharger, while also using the boost pressure sensor to verify that the boost pressure is correct.
This code is triggered when the PCM detects a low voltage signal indicating low boost pressure, despite a high pressure command being sent to the boost control solenoid “B”.
Symptoms
The symptoms of a P0241 code may include:
Due to the increased risk of damage to the catalytic converter and turbo over boost when P0241 is present, it is important to address this issue before continuing to use the vehicle.
Causes
Possible causes for this code to be triggered are:
Diagnostic and Repair Procedures
Before diagnosing P0241, make sure there are no other trouble codes stored in the PCM memory. If there are other DTCs present, they should be checked first. Any codes related to waste gate control or 5 volt reference can create the conditions necessary for this code to be triggered. In my experience, the PCM is the least likely cause of this problem. More often than not, it is chafed or burnt wiring near the turbocharger that causes shorts or breaks in the circuit.
It is always a good idea to start by checking for any technical service bulletins (TSB) specific to your vehicle. Your issue may be a known problem with a known solution provided by the manufacturer, which can save you time and money during diagnosis.
